The present invention relates generally to an indicating device, and in particular, to an indicating device for indicating the number of metered dosages of a substance, and in particular a medicament, that have been dispensed by, or remain in, a dispensing device.
Delivery systems, and in particular, dispensing devices, have been developed that include a counting or dose indicating device to indicate the number of metered doses of substance that have been dispensed from the delivery system, or to indicate the number of doses remaining therein. For example, patients have certain conditions that can be treated with medicaments dispersed in an aerosol and administered to the patient by inhalation. In one format, the aerosol and medicaments are contained in a container, and dispensed in metered, or measured, dosages with the dispensing device, which can include an actuator boot. In such an arrangement, it can be important for the patient to be able to ascertain the number of metered doses remaining in the container, either by an indication of the number remaining therein or by knowledge of the number already dispensed therefrom, such that the patient is not caught unaware with an empty container when in need of the medicament. Thus, it may be important for the dispensing device to provide an accurate indication of either the number of doses remaining in the container, or the number of doses already dispensed therefrom.
Typically, a conventional aerosol container includes a body and a valve stem which can be depressed relative to the body so as to emit the metered dose of aerosol and medicament. The container is usually supplied with a predetermined number of metered doses, e.g., on the order of about 200, such that the counting of the number of valve stem depressions, and corresponding number of dispensed metered doses, can be directly correlated with the number of doses remaining in the container.
In operation, the container is typically received within a housing of the dispensing device, wherein the valve is brought into engagement with a support block in the housing. The user administers the medicament by moving the container relative to the housing so as to depress the valve stem and internal valve and thereby release a metered dose, which is typically administered to the user through a port or mouthpiece extending from the housing. In an alternative delivery system, the metered dose can be first discharged into a chamber, and thereafter administered to the patient. After the metered dose is discharged from the container, the valve stem, which is typically spring loaded, biases the container away from the support block so as to again move the container relative to the housing. In this way, a metered dose of medicament is discharged by each cycle of linear reciprocal movement of the container relative to the housing.
Some dispensing devices have indicating devices that convert the linear reciprocal movement of the container relative to the housing into a one-way, or single-cycle, movement of an indicator, wherein the indicator identifies the relative fullness of the container, the number of metered doses remaining therein or the number of doses already administered. Although these dispensing devices with indicators have provided the advantage of generally being able to keep track of the number of dosages, there remains room for improvement. For example, indicating devices of this nature may include complex moving parts which can be difficult to assemble and expensive to manufacture. Such devices may also be susceptible to counting inaccuracies due to the configuration of the indexing or mating parts, or require excessive amounts of space within the housing to accommodate the relatively large or numerous moving parts. Others still may impede or interfere with the airflow and medicament being dispensed from the inhalation device. Alternatively, some devices use electrical circuitry to count or record the dispersements. Such devices can be relatively expensive to manufacture, however, and typically require a power source which may be susceptible to damage in various environments, such as moist conditions.
Briefly stated, in one aspect the invention is directed to a dispensing device having an indicating device. The dispensing device dispenses metered dosages of a substance from a container having a valve moveable between a closed position and an open position. The container dispenses a metered dosage when the valve, actuated by a valve stem, is moved to the open position. In an exemplary embodiment, the dispensing device includes a housing adapted to support the container reciprocally moveable within the housing along a longitudinal axis. The housing has a well adapted to receive the valve stem and an exhaust port. The well communicates with the port such that the metered dosage of substance is dispensed through the port when the valve stem is moved to the open position.
In one embodiment of the indicating device, an indicator assembly includes a worm rotatably mounted in the housing about an axis transverse to the longitudinal axis and responsive to the movement of the reciprocal movement of the container within the housing such that the longitudinal movement of the container relative to the housing causes the worm to rotate about its axis. An indicator member includes dosage indicia visible to a user and a circular gear mounted in the housing about an axis transverse to the axis of the worm and non-parallel to the longitudinal axis. The circular gear engages the worm.
In a preferred embodiment, the indicator assembly further includes a ratchet wheel rotatably mounted in the housing and adapted to be responsive to the reciprocal movement of the container relative to the housing along the longitudinal axis. The ratchet wheel is connected to the worm such that rotation of the ratchet causes the worm gear to rotate about its axis. In addition, an actuator member including an arm is preferably mounted within the housing and is adapted to move in response to the movement of the container and operably engage the ratchet wheel so as to rotate the wheel in response to the longitudinal movement of the container relative to the housing. Also in the preferred first embodiment, the indicator member includes an indicator wheel coaxially mounted with the circular gear on an axle defining the axis of rotation of the indicator member. The dosage indicia are applied to a surface of the indicator wheel.
In another embodiment of the indicating device, the housing comprises at least one engagement member and the indicator assembly includes a plurality of indicator members, including at least a first and second indicator member. The plurality of indicator members are coaxially mounted in the housing. At least one of the first and second indicator members includes an advancement member, while at least the other of the first and second indicator members includes a plurality of teeth. In operation, the first indicator member is rotated relative to the second indicator member such that the engagement member selectively engages and biases the advancement member into operable engagement with at least one of the plurality of teeth so as to rotate the second indicator member an incremental amount.
In a preferred embodiment, an actuator member is mounted in the housing and is responsive to the movement of the container. The actuator member selectively engages at least one of the plurality of teeth on the first indicator member so as to advance the first indicator member an incremental amount in response to the movement of the container relative to said housing. A spring is preferably disposed in the housing to bias the actuator member into engagement with the container.
In another aspect of the invention, the indicator assembly, including the ratchet wheel, worm, actuator member and indicator member of the first embodiment, are mounted within an indicator module which is adapted to be mounted within the dispenser housing. Similarly, with respect to the second embodiment, the indicator assembly, including the plurality of indicator members, advancement member, spring and ratchet member, are supported in the indicator module. The module preferably includes a first and second member which are joined to form an enclosure or housing, and which support any one or more of the ratchet wheel, worm, actuator member and indicator member of the first embodiment therein, or the plurality of indicator members, advancement member, spring and actuator member of the second embodiment. In the second embodiment, the engagement members are also preferably disposed in the module housing.
In another aspect of the invention, a key member is mounted to one of the container and the housing and is shaped to be received in a passageway formed in the other of the housing and container.
In yet another aspect of the invention, a method is provided for dispensing measured dosages from the container. In one embodiment, the method includes the steps of moving the container along the longitudinal axis so as to move the valve stem, and valve, to the open position wherein a metered dosage is discharged. The longitudinal movement of the container within the housing causes the ratchet gear to rotate a predetermined angular amount, which, in turn, causes the worm to rotate about its axis. The worm then engages the circular worm gear of the indicator member so as to rotate the worm gear about its axis.
Alternatively, in a second embodiment, the first indicator member is rotated a predetermined amount in response to the movement of the valve between a closed and open position, or vice versa. Upon a predetermined number of movements of the valve, the first indicator member causes the second indicator member to rotate a predetermined amount.
In another aspect of the invention, a method is provided for assembling a dispenser comprising a housing, a container and an indicator module.
In yet another aspect of the invention, a kit includes components capable of being assembled as a dispensing device for dispensing metered dosages of a substance from a container. The kit includes a housing, a container having a plurality of metered dosages of the substance and an indicator module having an indicator member.
The present invention provides significant advantages over other indicating devices. In particular, with respect to the first embodiment of the indicating device, the worm provides for a compact drive component that does not occupy excess space within the housing. Moreover, the worm provides for high gear reduction ratios while maintaining a continuous engagement with the circular worm gear. The continuous engagement of the worm and circular gear ensures that the accuracy of the counting device is maintained, while simultaneously simplifying the manufacturing and assembly process.
The use of a circular gear having an axis non-parallel, and preferably transverse or perpendicular to the longitudinal movement of the container within the housing, also provides several advantages. Importantly, the gear can be easily mounted to the housing with an inexpensive and easy-to-install axle. Thus, the circular gear provides for a compact single-cycle device that fits easily into the housing, and which maintains continuous engagement with the worm gear for improved and accurate indexing of the indicator member. Moreover, the components are arranged so as to not interfere with or otherwise impede the air flow from the valve stem to the exhaust port of the housing. In addition, the indicator wheel, which is preferably coaxially mounted with the worm gear, provides an ideal planar surface for displaying the dosage indicia. The indicia can be easily viewed by the user through the viewing window.
The second embodiment of the indicating device provides similar advantages. In particular, the plurality of indicator members can be mounted in a compact arrangement to provide accuracy and reliability under various operating conditions but which does not impede or obstruct the airflow to the user. Moreover, the various parts are relatively inexpensive to manufacture and assemble. The indicia, which are visible to the user through the viewing window, are easy to read and readily accessible to the user.
The indicator module, with any of the various embodiments of indicating assemblies disposed therein, also presents several advantages. In particular, the self-contained unit can be separately manufactured and installed as needed in any number of conventional types of dispensing devices with minimal modification thereof. Moreover, the module can be easily installed without interfering with or otherwise impeding the air flow from the valve stem to the exhaust port and ultimately to the user.
The key member also presents several advantages. In particular, differently configured key members and passageways can be installed between containers holding different substances such as medicaments and corresponding delivery system housings so as to prevent the user from interchanging various containers and housings so as to thereby alter the number of doses being counted. The key member and passageway can also prevent a user from using the wrong delivery system for a particular container having a particular substance, such as a medicament.